完成了红外搜索与跟踪(IRST)系统中光学系统的设计,工作波段为8-12 μm。首先分析了IRST系统的特性,详细介绍了其光学系统的组成。系统结构采用卡塞格林反射式,通过折/衍混合元件校正剩余像差,完成了二次成像。通过简单机电方式补偿热差,使系统在-40 ℃-+60 ℃温度范围内性能均接近衍射极限。通过对主镜和次镜加遮光罩的措施抑制系统杂散光,使红外探测系统的信噪比得以提高,图像对比度得到增强。实验结果表明,此系统性能良好。

A Cassegrain optical system of infrared search and trace (IRST) working at 8-12 μm is introduced.After analyzing the characters of the IRST system,the compositions of the optical system are described.A diffractive optical element (DOE) is successfully introduced to the second imaging to correct ray aberrations,which makes the system working well at room temperature.In order to make the system work in a wide thermal environment,an electromechanical device is utilized to control the compensation lenses.To suppress the great amount of stray light,lens hood is set on the primary and secondary mirrors,which could eliminate stray light efficiently.Hence signal-to-noise ratio and contrast of the picture have been enhanced.The experiment shows that the system works well.